In the case of a clutch thrust bearing, it happens that the axis of the diaphragm clutch mechanism is not strictly in line with the axis of the output shaft of the gearbox, which may lead to high stresses on certain portions forming the clutch thrust bearing, to the point of limiting the service life of this type of equipment. Defects of alignment between the aforementioned axes may be such that these axes are not superimposed, while being parallel, or that these axes intersect. In this second case, the alignment defects have hitherto been relatively minor, which allows a conventional clutch thrust bearing to accommodate them.
If such an alignment defect becomes relatively major, particularly if the axes form between them an angle greater than 2°, the diaphragm of the clutch mechanism may press unevenly on the outer ring of the thrust bearing, which causes uneven wear. Because of the complexity of the mechanism, increasing notably since the emergence of dual clutches, and for economic reasons, the manufacturing tolerances of certain parts forming a clutch tend to increase, so that the angle of offset between the input and output axes of a clutch thrust bearing tends to increase to values greater than 2°.
To alleviate this drawback, it is known from WO-A-2007/137939 to produce a swivel joint between an inner ring, an adjustment ring and a sliding ring of a clutch thrust bearing. The use of adjustment and sliding rings, which are additional parts relative to a conventional thrust bearing, increases the cost price of this equipment and makes its installation more complex. Moreover, the axial space requirement of the thrust bearing is increased.
It is also known from US-A-2004/0033000 to produce, in the outer ring of a clutch thrust bearing, a track in the shape of a section of a sphere on which the balls can have a certain range of travel making it possible to adjust the position of the central axis of the inner ring relative to the position of the central axis of the outer ring. The volume lying between the inner and outer rings of such a thrust bearing must be insulated from the outside and a seal must be provided for this purpose, such a seal being more or less compressed depending upon the position of the balls on the travel track, which may cause premature wear of this seal.
Problems of the same kind arise with other ball bearings forming an axial-force transmission member such as, for example, bump stops of motor vehicles.